1. Field of the Invention
This invention relates to an installation for lubricating, cleaning and/or disinfecting conveyor belts for containers, more particularly for foods, such as bottles, glasses, cans, bags and the like. The installation comprises at least one central metering station--designed for connection to a water pipe--for diluting a concentrated lubricant, cleaner or disinfectant and several distributing pipes connected to the metering stations and leading to the points of use.
2. Description of the Related Art
In the food industry, the food containers, for example beverage bottles, are transported on conveyor belts, more particularly slat belts, hinged chains and the like. Thus, beverage bottles have to be transported from the unpacking station to the washing machine, to the filler, to the labeling machine and to the packing station. In the beverage industry, for example in breweries, the washing, filling and labeling of bottles is mainly carried out automatically. Accordingly, the high-speed conveyor belts, which are made of stainless steel or plastic, have to be lubricated with a chain lubricant which is also known as a "belt lubricant". In addition, the conveyor belts have to be cleaned and/or disinfected at more or less regular intervals. The necessary concentration of the chain lubricant depends on a number of parameters, including for example the belt speed, the surface quality and the loading of the belts. For this reason, different concentrations have to be used depending on where the lubricant is applied.
The present state of the art in belt lubrication is described in detail in an article in the journal "Brauwelt", Vol 131 (1991), No. 44, pages 2026-2032. Reference is made to that article to complete the disclosure of the present invention.
The cleaners, disinfectants and belt lubricants are supplied as concentrates by the manufacturers and, in the food-processing plant, are applied to the conveyor belt, for example by spraying, after dilution with water to the particular in-use concentration required. The solution then runs off the belt into a wastewater channel via a collector.
The solution to be used with the particular concentration required may be prepared from the concentrate as supplied by the manufacturer in various ways. Thus, the concentrates may be taken to the points of use, diluted with water to the particular in-use concentration and directly used. Various metering systems, for example injectors, metering pumps or other volume- or time-controlled and quality-controlled systems, may be used for dilution. However, the concentrates have to be transported to the particular points of use within the plant and separate metering systems have to be provided for each point of use.
Although the concentrate could in principle be transported from the chemicals storeroom to the points of use through a pipe, this would not be appropriate because the corresponding concentrate--as a water-endangering and caustic liquid--should not be transported through production rooms and work rooms. In addition, the blending of two liquid streams in a ratio of 1:200 to 1:1000 through a blending valve is technically very complicated if it is to be carried out with the necessary accuracy.
In another variant, the concentrates are diluted to the required in-use concentration in a central metering station. The solution thus prepared is then transported to the points of use through distributing pipes. The present invention is concerned with the further development of such central conveyor belt lubrication systems. Various concentrations of the solutions intended for the individual points of use are possible, but do require several central metering stations which transport the solutions to the conveyor belts through separate distributing pipes. This requirement means additional expenditure on metering technology and pipes.
With a conventional metering system based on diaphragm metering, cleaning, disinfecting and belt lubricating solutions intended for direct throughputs of 5 m.sup.3 /hour or higher are extremely difficult to prepare with a uniform distribution of concentration for variable flow rates.
This is attributable above all to the limited metering frequency of the diaphragm metering pumps. When the maximum metering frequency is reached, a higher throughput of the in-use solution with the necessary concentration can only be achieved by increasing the amount added during each individual stroke of the diaphragm pump. As a result, the proportional amount added cannot be uniformly mixed in the pipe.